The Add In Manager is a crucial Revit Add-In for developers, the process of restarting Revit is quite slow and prevents you from effectively iterating while developing without using the AIM to dynamically load in DLLs at runtime. It is hands down probably the most crucial part of the SDK outside of the API itself.
However, it still has numerous bugs (such as this major one that still is not solved despite the thread tag) and hasn't been updated in several years. When bugs regarding the Add In Manager get brought up the general response is that the development team doesn't have time to go back and revisit the Addin Manager code. Since it is just an add in and not part of the Revit core, the natural solution seems like it would be to open source it, similar to RevitLookup. This would allow Revit developers to help maintain it, and spend their time fixing it rather than coming up with convoluted workarounds for its bugs.
In short, please open source the Add In Manager!
